We have refined our existing model for myocardial and ventricular mechanics to include the effects of collagen on the elasticity of the myocardium and filling of the left ventricle, wall thickness and curvature effects, pathological fiber organization, myocardial blood flow, myocardial oxygen demand, and effects of electrical activation patterns. The model was used in conjunction with ultrasonic kinematic data, gated radionuclide ventriculography, and left heart catheterization data to determine performance parameters. The physiological relationships between phasic coronary arterial, venous, and left ventricular pressure and blood flow, were determined during a long diastole and control conditions A mathematical and physical model of myocardial blood flow was developed incorporating vessel collapse at the University of Paris XII. Also RF absorbtion from the myocardium was investigated experimentally at the University of Paris XII and INSERM U 138 to determine the effect of loading on the spectral absorbtion coefficient. A theoretical model was developed to describe contraction of arterioles, and will be used to study mechanisms of hypertension. A model investigating the intraction of the right and left ventricles is being developed.